The donor-supply electrode enhances performance in colloidal quantum dot solar cells

Pouya Maraghechi, André J. Labelle, Ahmad R. Kirmani, Xinzheng Lan, Michael Adachi, Susanna Thon, Sjoerd H. Hoogland, Anna Lee, Zhijun Ning, Armin H. Fischer, Aram Amassian, E. H. Sargent

Research output: Contribution to journalArticlepeer-review

115 Scopus citations

Abstract

Colloidal quantum dot (CQD) solar cells combine solution-processability with quantum-size-effect tunability for low-cost harvesting of the sun's broad visible and infrared spectrum. The highest-performing colloidal quantum dot solar cells have, to date, relied on a depleted-heterojunction architecture in which an n-type transparent metal oxide such as TiO2 induces a depletion region in the p-type CQD solid. These devices have, until now, been limited by a modest depletion region depth produced in the CQD solid owing to limitations in the doping available in TiO2. Herein we report a new device geometry - one based on a donor-supply electrode (DSE) - that leads to record-performing CQD photovoltaic devices. Only by employing this new charge-extracting approach do we deepen the depletion region in the CQD solid and thereby extract notably more photocarriers, the key element in achieving record photocurrent and device performance. With the use of optoelectronic modeling corroborated by experiment, we develop the guidelines for building a superior CQD solar cell based on the DSE concept. We confirm that using a shallow-work-function terminal electrode is essential to producing improved charge extraction and enhanced performance. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)6111-6116
Number of pages6
JournalACS Nano
Volume7
Issue number7
DOIs
StatePublished - Jun 7 2013

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-11-009-21
Acknowledgements: This publication is based in part on work supported by Award KUS-11-009-21, made by King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The authors would like to acknowledge O. Voznyy for XPS measurements and analysis. A. J. Labelle would like to acknowledge an OGS scholarship. M. M. Adachi was supported by a MITACS fellowship. X. Lan would like to acknowledge a scholarship from the China Scholarship Council (CSC). The authors would like to acknowledge the assistance of E. Palmiano, R. Wolowiec, and D. Kopilovic.

ASJC Scopus subject areas

  • General Physics and Astronomy
  • General Materials Science
  • General Engineering

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